SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '982b7df9e300add9675f354bd287fa30cb2bca4cc6103466e52566a0dbbe850d' 
  AND token = '5xR8lRkU+zleFaamcDGVgbtBQ8FAfweE3VwYE5oXTJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}